psychology of wealth

There is a form of inactive, extravagant wealth given over wholly to pleasure, the enjoyer of which on the one hand behaves as a mere ephemeral individual frantically spending himself to no purpose, and also regards the slave-labour of others (human sweat and blood) as the prey of his cupidity. He therefore knows man himself, and hence also his own self, as a sacrificed and futile being. With such wealth contempt of man makes its appearance, partly as arrogance and as squandering of what can give sustenance to a hundred human lives, and partly as the infamous illusion that his own unbridled extravagance and ceaseless, unproductive consumption is the condition of the other’s labour and therefore of his subsistence.
—  Marx - Economic Manuscripts 1844

The smartphone you prefer can give people clues about your personality. Researchers found that iPhone users are often younger, more likely to see their phone as a status symbol, and more extroverted, while Android users are generally older, more honest, and less interested in wealth or status. Source Source 2

The desire after hoarding is in its very nature unsatiable. In its qualitative aspect, or formally considered, money has no bounds to its efficacy, i.e., it is the universal representative of material wealth, because it is directly convertible into any other commodity. But, at the same time, every actual sum of money is limited in amount, and, therefore, as a means of purchasing, has only a limited efficacy. This antagonism between the quantitative limits of money and its qualitative boundlessness, continually acts as a spur to the hoarder in his Sisyphus-like labour of accumulating. It is with him as it is with a conqueror who sees in every new country annexed, only a new boundary.
—  Marx - Capital Vol 1 Ch.3 1867